In recent years, a wireless charger for wirelessly charging a built-in battery of a portable device through the installation of a primary coil in the charger and the installation of a secondary coil in the built-in battery of the portable device has been developed.
In order to charge the battery by using such a wireless charger, the alignment of the primary coil and the secondary coil is important, so that a user should place the portable device in a designated position of a wireless charging pad.
However, even when the user places the portable device in the designated position of the wireless charging pad, impacts or the like may change the position of the portable device during battery charging, which causes inconvenience to the user as the user has to manually move the portable device to the designated position of the wireless charging pad.
For example, when the wireless charger is applied to a vehicle, a driver may move a portable device on a wireless charging pad to a designated position while driving, which interrupts safe driving and is also against the road traffic law.
In order to solve the above problem, a wireless charger for aligning a portable device by using a magnetic substance has been proposed as a related art. That is, the wireless charger includes the magnetic substance and the portable device includes a metal plate, such that the magnetic substance attracts the metal plate due to magnetic attraction and the portable device is aligned in an appropriate position.
According to the related art, in consideration of the weight of the portable device or the like, a considerable level of magnetic force is required to align the portable device in an appropriate position with only the magnetic attraction. The magnetic force may affect the operations of the portable device and may also deteriorate the inductive coupling of the primary coil and the secondary coil.
In addition, when a geomagnetic sensor, a gyrosensor, or the like is provided in the portable device, the magnetic force of the magnetic substance may cause the malfunction of the portable device.